JP2971298B2 - Protective relay - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection relay for judging the state of an electric power system by using a digital computer and protecting the equipment, in particular, a scalar addition amount and a vector of each current amount taken in from a plurality of systems via CT. It relates to a protective relay that detects an accident in the power system by comparing the added amount.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a principle diagram showing a conventional ratio differential protection relay shown in Japanese Unexamined Patent Publication (Kokai) No. H11-207, in which 21 is a rectifying / smoothing element for rectifying and smoothing a current amount of a system obtained via a CT, and 22 is a CT. A vector addition element for adding the respective current amounts of the system obtained through the vector, a scalar addition element for adding the rectified and smoothed current amounts, and an output of the vector addition element 22, that is, a vector addition amount. A vector addition amount rectifying / smoothing element 25 for rectifying / smoothing is an output of the scalar addition element 23 and the vector addition amount rectifying / smoothing element 24.
, That is, a comparison element for judging the vector addition amount (movement amount) and the scalar addition amount (suppression amount), and 26 is an output element for outputting the judgment result of the comparison judgment element 25. is there.

Next, the operation will be described. The operation principle of FIG. 8 is shown by the following arithmetic expressions (1) and (2).

[0004]

(Equation 1)

Next, the operation of FIG. 8 will be described. That is,
The amount of current Ii ^t rectification smoothing element 21 of each of the sampled power system, (2) the rectified and smoothed by ‖Ii ^t ‖ next, each current is the rectifier smoothing as expressions are summed by scalar summation element 23 And the above equation (1)
B term. On the other hand, is a vector added by the amount of current Ii ^t vector summation element 22 of people each of the sampled power system further vector addition amount rectifying and smoothing elements 2
4 and is rectified and smoothed to become the A term in the above arithmetic expression (1). In the comparison determination element 25, normally, the output of the scalar addition amount 23 (the B term of the arithmetic expression (1)) is multiplied by an appropriate constant, and the output of the vector addition amount rectifying / smoothing element 24 (the arithmetic expression (1 The determination of the expression (1) is performed together with the A term) of the above). As a result, if the equation (1) is satisfied, the operation signal is output from the comparison / determination element 25. The output element 26 gives an appropriate time limit to the above operation signal and outputs it as a final operation signal.

In the above equation, K _{0 in} equation (1) is used.
In order to obtain the differential characteristic shown by the solid line (a) in the operational characteristic of the general differential protection relay in FIG. 9 with the minimum operating value and K ₁ as the ratio, it is not necessary to simply rectify the instantaneous value. Since a pulsating flow occurs and the operating characteristics vary depending on the sampling phase, it is necessary to perform rectification and smoothing as in the above equation (2), for example. By the calculation of the equation (2), a form such as four-phase rectification can be obtained, the operating value error can be reduced, and the variation of the differential characteristics due to the sampling phase is reduced.

[0007]

Since the conventional protective relay is configured as described above, the constant K _{0 is} automatically determined by the magnitude of the current amount in order to avoid a malfunction due to the saturation of the CT at the time of an external accident. While the slope of the differential characteristic by changing the K ₁ is subjected to measures such'll change greatly at a large current region, not exhaustive, example 1 CT is CT2 primary current is momentarily completely saturated terminal In the case where the value becomes 0, malfunction may occur. The present invention has been made to solve the above-mentioned conventional problems, and has as its object to obtain a protective relay that is stable even when CT is saturated.

[0008]

According to a first aspect of the present invention, there is provided a protection relay device for comparing a scalar addition amount and a vector addition amount of each current amount taken in via a CT from a plurality of systems. In the protective relay for detecting an accident in the power system, a vector addition element for vector addition of each current amount of only the load line, and a determination element for detecting the saturation of the CT based on the output of the vector addition element are provided. The relay output is locked by the output of the element.

According to a third aspect of the present invention, there is provided a protective relay device comprising: an effective value calculating element for deriving an effective value of a current amount of only the load line from an output of a vector adding element; A determination element for detecting the saturation of the CT by comparing the current effective value with the effective value before the current is provided, and the output of the determination element locks the relay output.

According to a fourth aspect of the present invention, the protection relay device detects the saturation of the CT by comparing the current effective value of the effective values derived by the effective value calculation element with the effective value before the present. A second determining element for determining whether the derived effective value is larger or smaller than a predetermined value,
A third determination element for detecting the saturation of the second determination element, and an OR element for performing an OR operation on the output of the second determination element and the output of the third determination element. The output of the relay is determined by the output of the OR element. It is intended to be locked.

According to a fifth aspect of the present invention, there is provided a protective relay device comprising: a first effective value calculating element for deriving an effective value of a current amount of only the load line from an output of a vector adding element; A second determination element for detecting the saturation of CT from the effective value derived by the element, an algorithm different from the first effective value calculation element for determining the effective value of the current amount of only the load line from the output of the vector addition element , A third determination element for detecting the saturation of CT from the effective value derived by the second effective value calculation element, and an output of the second determination element and the second determination element. An OR element for ORing the output of the judgment element 3 is provided, and the output of the relay is locked by the output of the OR element.

According to a sixth aspect of the present invention, there is provided a protective relay device for detecting the saturation of the CT from the effective value of the current amount of only the load line derived by the effective value calculation element of the vector addition element.
From the effective value derived by the effective value calculation element by a determination function different from the second determination element.
A third determination element for detecting the saturation of T, the magnitude of the difference between the current output and the output before the current among the outputs of the vector addition amounts of the vector addition elements, and depending on the determination result, Fourth controlling the output of the second and third determination elements
And an OR element for inputting each output of the second and third judgment elements controlled by the fourth judgment element, and the relay output is locked by the output of the OR element. It was done.

[0013]

In the protective relay device according to the first and second aspects of the present invention, the output of the vector addition element for vector-adding each current amount of only the load line is used to determine the saturation of the CT. Since the output of the relay is locked, a malfunction of the relay can be reliably prevented against the CT saturation phenomenon at the time of an external accident, and a protection relay device having a protection performance capable of correctly responding to a power system accident at a high speed is provided. can get.

[0014] In the protective relay device according to the third aspect of the present invention, the current effective value of the effective value derived from the current amount of only the load line from the output of the vector addition element,
Since the output of the relay is locked by the output of the determination element that detects the saturation of CT by comparing with the effective value before the present, the CT saturation phenomenon at the time of an external accident is detected with high sensitivity.

In the protection relay device according to the present invention, the saturation of CT is detected by comparing the current effective value of the effective values derived by the effective value calculation element with the effective value before the present. The output of the second determination element to perform the above operation and the output of the third determination element for detecting the saturation of the CT by determining whether the derived effective value is larger or smaller than a predetermined value are output from the relay. Since the output is locked, that is, the output of the relay is locked by the elements of the detection function which are duplicated and different from each other, the CT saturation phenomenon is more reliably detected.

In the protective relay device according to the present invention, the saturation of the CT is detected from the effective value derived by the first effective value calculating element for deriving the effective value of the current amount of only the load line. The output of the second determination element and the effective value of the current amount of only the load line are derived from the effective value derived by the second effective value computing element which is derived by an algorithm different from that of the first effective value computing element. Since the output of the relay is locked by the logical sum output with the output of the third determination element for detecting the saturation of CT, the CT saturation phenomenon can be detected more accurately.

In the protection relay device according to the present invention, a second determination element for detecting the saturation of the CT from the effective value of the current amount of only the load line, and a determination different from the second determination element. A third determining element for detecting the saturation of the CT from the effective value, and a magnitude of a difference between the current output and the output before the current among the outputs of the vector addition amounts of the vector addition elements by the function; A fourth determination element for controlling the output of the second and third determination elements depending on the determination result is provided, and the fourth and third determination elements controlled by the fourth determination element are provided. Since the output of the OR element for inputting each output locks the relay output, even when the CT saturation angle is small, the operation speed of the relay in the event of an accident becomes faster rather than slower.

[0018]

[Embodiment 1] Embodiment 1 of the present invention will be described below with reference to the drawings. In FIG. 1, 1L, 2L, 1F, 2
F, 3F, and 4F are input terminals of the protective relay. Among these input terminals, input terminals 1L and 2L sample a power line current detected from a power line of a power system via a CT (not shown). The obtained sampled power supply line current (instantaneous value) is input, and the input terminals 1F, 2F, 3F, and 4F receive the load line current detected via the CT (not shown) from the load line of the power system. A sampled load line current (instantaneous value) obtained by sampling is input. Reference numeral 1 denotes a rectifying element having an AC side connected to each of the input terminals 1L, 2L, 1F, 2F, 3F, and 4F, which rectifies the amount of current of the sampled system. Reference numeral 2 denotes a maximum value deriving element for deriving the instantaneous maximum value of the rectified current, which derives the suppression amount of the ratio differential relay. Reference numeral 3 denotes a first vector addition element which has an input side connected to each of the input terminals 1L, 2L, 1F, 2F, 3F, 4F and adds a vector to the sampled current amount (instantaneous value). This is to derive the differential amount of the relay. A first determination element 4 receives the output of the maximum value derivation element 2 and the output of the first vector addition element 3 and compares and determines the magnitude relationship between the suppression amount and the differential amount. A first operation return matching element to which an output of the first judgment element 4 is input, and an operation signal when the operation output of the first judgment element 4 becomes equal to or more than a predetermined time (or a predetermined number of operation outputs); And output
Thereafter, it is a first operation return collation element that does not return immediately after the output of the first determination element 4 recovers but returns after a predetermined time (or a predetermined number of times). A is a protection relay function route by the rectifying element 1, the maximum value deriving element 2, the first vector adding element 3, the first determining element 4, and the first operation return collating element 5.

Reference numeral 6 denotes each of the input terminals 1F, 2F, 3F, 4
F, the input side of which is connected to each of the F and the vector amount of the current amount (instantaneous value) of each of the sampled load lines is added.
, A storage element 7 for storing the output of the second vector addition element 6, 8 a vector addition amount output (instantaneous value) of the second vector addition element 6, an output of the storage element 7, , And calculates the effective value of the load line by calculating the sum of squares of the vector addition amount by the vector addition element 6 and the vector addition amount (instantaneous value) several samples before stored in the storage element 7. Element 9 is a second judgment element which receives the output of the effective value calculation element 8 and compares the above sum of squares with a reference value to judge and output the sum according to the magnitude relation.
10 outputs an operation signal when the operation output of the second determination element becomes equal to or longer than a predetermined time (or a predetermined number of operation outputs), and then immediately after the output of the second determination element 9 returns. , A second operation return collating element that returns after a predetermined time (or number of times) without returning to the first operation return collating element 5 and the output of the second operation return collating element 10 And locks the output of the first operation return collating element 5 with the output of the second operation return collating element 10. B is C by the above-described second vector addition element 6, storage element 7, effective value calculation element 8, second determination element 9, and second operation return collation element 10.
It is a T saturation detection route.

When the block diagram of FIG. 1 is implemented by a program using a digital computer, a flowchart of its functions is as shown in FIG. Hereinafter, the operation of the first embodiment will be described with reference to FIG.

First, the protection relay function route A will be described. First, the operation side route of the first determination element 4 (ratio differential element) will be described. In step 1, calculate the maximum value E _R ^t of absolute values of each of the power flow quantized by sampling the amount of current Ii ^t strains in t time (the suppression amount) at the maximum value deriving element 2. In Step 2, over the amount of electricity Ii ^t first vector addition elements 3 of the respective adding the quantity of electricity of the entire power supply line and a full load line, to calculate the E _DLF ^t (differential amount). In step 3, the magnitude relationship between the differential amount E _DLF ^t and the suppression amount E _R ^t is compared by a first determination element 4, and if the former is greater or equal, that is, the first determination element 4 (ratio If the differential element has operated, the operation proceeds to step 4, and if the latter is large, the operation proceeds to step 9.

In step 4, the number of operations of the first determination element 4 (ratio differential element) is counted by the first operation return collation element 5, and then the operation proceeds to step 5. In step 5,
The count value of the first operation return collation element 5 is set in the operation number counter CNT _D0 of the ratio differential element, and the process proceeds to step 6. In step 6, the operation counter C
Compare the magnitude relationship between the set value of NT _D0 and the predetermined time N _D0 (number of times), and when the former is greater or equal,
Proceeding to step 7, if the latter is large, exit from the processing route. In step 7, the operation flag of the ratio differential element is set, and the process proceeds to step 8. This means that the input of the inhibit element 11 has become logic "1". In step 8, the first operation return collating element 5 does not return immediately after the output of the first determination element 4 returns, but returns after a predetermined time (the number of operations of the first determination element 4). A predetermined number of return collation times, for example, the set value of the operation number counter CNT _D0 is returned to a return collation counter C
Set to NT _DR and proceed to step 42.

Next, the return route of the ratio differential element will be described. In step 9, the value of the return collation counter CNT _DR is compared with 0. If they are equal, the process proceeds to step 11, and if they are not equal, the process proceeds to step 10. In step 11, since the ratio differential element (first determination element 4) is not operating, the ratio differential operation flag is reset, and step 12
Proceed to. In step 12, the operation counter CNT _D0 is reset, and the process proceeds to step 42. In step 10,
The value of the number of times of return collation of the return collation counter CNT _DR is decremented, and the process exits the processing route.

Next, the CT saturation detection route B will be described. First, the CT saturation operation side route will be described. In step 31, the electric quantity Ii ^t by adding the amount of electricity only a full load line with the second vector summing element 6, to calculate the total E _DF ^t by vector addition of the load line current drain. In step 32, the effective value calculated based on the output value of the second vector addition element 6 and the output value of the storage element 7 is compared with a predetermined current amount by a second determination element (overcurrent element) 9,
When the former is larger or equal, that is, when the second determination element 9 operates, the process proceeds to step 33, and when the latter is larger, the process proceeds to step 38.

In step 33, the number of operations of the second determination element (overcurrent element) 9 is counted by the second operation return collation element 10, and the process proceeds to step 34. In step 34, the second operation return verification element 10 is set in the overcurrent element operation number counter (operation verification counter) CNT0C0.
Is set, and the routine proceeds to step 35.

In step 35, the operation collation counter C
The above set value of NT _0C0 is compared with a predetermined time N _0C0 (number of times), and when the former is larger or equal,
That is, when it is determined that the CT is saturated, the process proceeds to step 36,
When the latter is large, the process exits the processing route. Step 3
At step 6, the operation flag of the CT saturation detection element is set, and the routine proceeds to step 37. This means that the inhibit side input of the inhibit element 11 has become logic "1".
In step 37, the second operation return collation element 10 does not return immediately after the output of the second determination element 9 returns, but returns after a predetermined time (the number of operations of the second determination element 9). predetermined reset verification number, for example, the set value of the operation number counter (operation verification counter) CNT _0C0, is set to return matching counter CNT _0CR, the process proceeds to step 42.

Next, the CT saturation non-operation side route will be described. In step 38, the process proceeds to step 40 if the value of the return collation counter CNT _0CR is compared with 0, and if not, the process proceeds to step 39. In step 39, the value of the number of times of return collation is decremented, and the process exits the processing route. In step 40, the operation plug of the CT saturation detection element is reset, and the process proceeds to step 41. Step 4
In step 1, _CNT0C0 is reset, and the process proceeds to step 42.

In step 42, the inhibit 11 is determined. If the condition of "ratio differential element operation and CT saturation detection element non-operation" is satisfied, the process proceeds to step 43.
The overall operation, that is, an output from the inhibit element 11, and a signal indicating an internal accident is output.
"Ratio differential element operation and CT saturation detection element non-operation"
If the condition other than the condition (1) is satisfied, the process proceeds to step 44, in which the overall operation is not performed.

Embodiment 2 FIG. In the first embodiment, the second
In the second embodiment, the second storage element 12 is provided as shown in FIG. 3, and the effective value calculation element 8 is provided. The CT saturation is detected by accumulating the data calculated in step (1) and detecting the effective value change width (increment) by comparing the effective value data before 180 ° with the current effective value data. The specific effect is as described above. CT with higher sensitivity compared to Example 1
This makes it possible to detect saturation.

The second embodiment will be described below with reference to FIG. In FIG. 3, 1 to 8, 10, and 11 are the same as in the first embodiment, and a description thereof will be omitted. Reference numeral 12 denotes a second storage element for inputting the output of the effective value calculation element 8, which stores the effective value calculated by the effective value calculation element 8 for a required time (number of times). The second determination element 9 receives the output of the effective value operation element 8 and the output of the second storage element 12, and outputs the current effective value, which is the output of the effective value operation element 8, and the second storage Take the difference from the rms value a few samples ago stored in element 12,
The difference is compared with a predetermined value, and the result is determined and output based on the magnitude relation therebetween.

That is, the effective value data 180 ° before and stored in the second storage element 12 and the effective value calculation element 8
The CT saturation is detected by the effective value change width (increment) detection by comparing the current effective value data with the current effective value data, so that the CT saturation can be detected with high sensitivity. Also in the case of the second embodiment, FIG. 4 shows a functional flowchart in the case where the program is realized by using a digital computer, but the flowchart of FIG. Only the difference between the “change width” and the “overcurrent” is the same, and the description of the operation is omitted.

Embodiment 3 FIG. In the above-described first and second embodiments, the CT saturation detection elements are overcurrent and current increment detection. However, in the third embodiment, as shown in FIG. As a special effect, CT saturation can be reliably detected by duplicating elements having different detection functions, and malfunction of the relay at the time of an external accident can be reliably prevented. Hereinafter, the third embodiment will be described with reference to FIG. In FIG. 5, 1 to 12 have been described in the first or second embodiment, and a description thereof will be omitted. Reference numeral 13 denotes a third judging element for inputting the output of the effective value calculating element 8, which compares the effective value output of the effective value calculating element 8 with a predetermined reference value, and outputs a judgment based on their magnitude relation. .
14 outputs an operation signal when the operation output of the third determination element 13 is equal to or longer than a predetermined time (or a predetermined number of operations), and thereafter, even if the output of the third determination element 13 returns. A third operation return collating element which does not return immediately but returns after a predetermined time (or number of times), 15 is the output of the second operation return collating element 10 and the output of the third operation return collating element 14 The output is input to the inhibit side of the inhibit element, and it becomes a double detection circuit with elements having different detection functions, so that CT saturation can be reliably detected, and malfunction of the relay at the time of an external accident is prevented. It can be reliably prevented. The operations and functions have both the operations and functions of the above-described first and second embodiments, and a description thereof will be omitted.

Embodiment 4 FIG. In the third embodiment, the second determination element 9 is determined by the output data of the effective value calculation element 8.
Although the basic calculation of the (incremental change width detection element) or the third determination element 13 (overcurrent element) has been performed, the third storage element 16 is provided as in the fourth embodiment shown in FIG. If the second effective value calculation element 17 is configured to calculate the effective value by another algorithm, a more accurate CT saturation detection circuit can be configured.

Embodiment 5 FIG. In the third embodiment, the second
The operation return collation time (number of times) of the operation return collation element 10 was a fixed value. In addition, since the smaller the CT saturation angle is, the faster the computation algorithm is used for the effective value computing element 8, the output of the effective value computing element 8 may be overshot and increased. In other words, the change width (increment) despite the fact that the load flow has been interrupted (at the time of an internal accident)
The detection element (second determination element 9) and the overcurrent element (third determination element 9)
Operates to lock the output of the ratio differential element (first determination element 4), during which time the output of the ratio differential element is not output, and the CT saturation detection element returns. For the first time, the output of the ratio differential element becomes effective. This means that the operation speed of the relay is delayed, which is a problem for the power system. Therefore, as shown in FIG. 7, a third storage element 16, a difference current detection element 18, and a fourth determination element 19 are provided to detect when the load power flow is interrupted and when a bus internal accident occurs, and At the time of disconnection and a bus internal accident, an operation verification time is automatically set so that the second operation return verification element 10 and the third operation recovery verification element 14 do not operate, and the ratio differential element (first The output of the judgment element 4) is not locked.

The fifth embodiment will be described below with reference to FIG. In FIG. 7, reference numerals 1 to 16 are the same as those in the above-described first to fourth embodiments, and are omitted. 18 is the second vector addition element 5
And the output of the third storage element 16, and the output of the third storage element 16 that stores the output instantaneous value of the second vector addition element 5 for a certain period of time. By calculating the differential current between the output of the second vector addition element 5 and the instantaneous value at the current time, it is possible to detect whether the fault is a bus internal fault or a bus external fault. Reference numeral 19 denotes a fourth determination circuit for inputting the output of the difference current detection element 18, and a predetermined determination circuit for determining whether the differential current calculated by the difference current detection element 18 is increasing or decreasing. The value is compared with the difference current. If the result of the comparison is that the load has been interrupted or an accident has occurred inside the bus, the second operation return verification element 10 and the third operation return verification element 14 are determined.
Are not activated, these operation return collating elements 1
The operation collation times of 0 and 14 are automatically set, and the output of the ratio differential element (first determination element 4) is not locked. Others are the same as those in the first to fourth embodiments, and thus description thereof is omitted. In each of the drawings described above, the same reference numerals indicate the same or corresponding parts.

[0036]

As described above, according to the first and second aspects of the present invention, the scalar addition amount and the vector addition amount of each current amount fetched from a plurality of systems via CT are compared to determine the power consumption. In a protection relay for detecting an accident in a system, a vector addition element for vector addition of each current amount of only a load line, and a determination element for detecting the saturation of the CT based on an output of the vector addition element are provided. The output of the relay is locked to prevent the malfunction of the relay in the event of a CT saturation phenomenon in the event of an external accident. There is an effect that an electric device can be obtained.

Further, the invention according to claim 3 is an effective value calculating element for deriving the effective value of the current amount of only the load line from the output of the vector addition element, and the current effective value of the derived effective value. A judgment element for detecting the saturation of the CT by comparing the effective value with the effective value before the present is provided, and the output of the judgment element is used to lock the output of the relay. There is an additional effect that sensitivity can be detected.

Further, according to a fourth aspect of the present invention, the saturation of the CT is detected by comparing the current effective value of the effective values derived by the effective value calculation element with the effective value before the present. A third determining element for detecting the saturation of the CT by determining whether the derived effective value is larger or smaller than a predetermined value, and an output of the second determining element and the third determining element. The output of the OR element is provided with a logical OR element, and the output of the logical OR element is used to lock the output of the relay. Elements having different detection functions are duplicated, so that the CT saturation phenomenon can be more reliably performed. Has the additional effect of being able to be detected.

According to a fifth aspect of the present invention, there is provided a first effective value calculating element for deriving an effective value of a current amount of only the load line from an output of a vector adding element. A second determination element for detecting the saturation of the CT from the derived effective value, and an effective value of the current amount of only the load line from an output of the vector addition element using an algorithm different from that of the first effective value calculation element. A second effective value calculation element to be derived, a third determination element for detecting the saturation of the CT from the effective value derived by the second effective value calculation element, and an output of the second determination element and the second determination element. Since an OR element for ORing the output of the judgment element 3 is provided and the output of the relay is locked by the output of the OR element, there is an additional effect that the CT saturation phenomenon can be detected more accurately.

The invention according to claim 6 is a vector addition element for vector-adding each current amount of only the load line, and the effective value of the current amount of only the load line derived by the effective value calculation element of this vector addition element. A second determination element for detecting the saturation of the CT from the value, and a third determination for detecting the saturation of the CT from the effective value derived by the effective value calculation element by a determination function different from the second determination element. Element, the magnitude of the difference between the current output and the output before the current among the outputs of the vector addition amounts of the vector addition elements, and the outputs of the second and third determination elements depending on the determination result. And a OR element for inputting each output of the second and third determination elements controlled by the fourth determination element, and a relay is provided by the output of the OR element. Lock output Since the, relay operating speed at the time of the accident there is an additional effect that it becomes faster.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the principle of Embodiment 1 of the present invention.

FIG. 2 is a flowchart showing an operation flow according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a principle diagram of Embodiment 2 of the present invention.

FIG. 4 is a flowchart illustrating an operation flow according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing the principle of Embodiment 3 of the present invention.

FIG. 6 is a block diagram showing the principle of Embodiment 4 of the present invention.

FIG. 7 is a block diagram showing the principle of Embodiment 5 of the present invention.

FIG. 8 is a block diagram showing the principle of a conventional differential protection relay.

FIG. 9 is an operation characteristic diagram of a general differential protection relay.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rectification element 2 Maximum value derivation element 3 1st vector addition element 4 1st judgment element 5 1st operation return collation element 6 2nd vector addition element 7 Storage element (1st storage element) 8 Effective value calculation Element (first effective value calculation element) 9 Second determination element 10 Second operation return collation element 11 Logical inhibit element 12 Second storage element 13 Third determination element 14 Third operation return collation element 15 Logical Sum element 16 Third storage element 17 Second effective value calculation element 18 Difference current detection element 19 Fourth determination element

Claims (6)

(57) [Claims] 1. A protection relay for detecting an accident in a power system by comparing a scalar addition amount and a vector addition amount of each current amount taken in from a plurality of systems via CT, and detects each current amount of only a load line. A protection relay device comprising: a vector addition element for adding a vector; and a determination element for detecting the saturation of the CT based on an output of the vector addition element, and an output of the relay is locked by an output of the determination element. 2. A first vector addition element that takes in instantaneous values of current amounts from a plurality of systems and adds a vector, a maximum value derivation element that derives an instantaneous maximum value of the current amounts of the plurality of systems, and the first vector A first determination element for comparing the output of the addition element with the output of the maximum value derivation element to determine which output is larger, and counting the output duration or the number of outputs of the first determination element, A first operation return collation element that is output as a count value, a second vector addition element that vector-adds the instantaneous value of the current amount of only the load line, and an instantaneous value of the vector addition amount of the second vector addition element are stored. A storage element, an effective value operation element for calculating an effective value from the output of the second vector addition element and the output of the storage element, and a second element for determining whether or not the output of the effective value operation element is equal to or greater than a predetermined value. of A determination element, a second operation return collating element that counts the output duration or the number of outputs of the second determination element, and outputs a predetermined count value, and outputs the first and second operation return collation elements. As the input, the first
A protection relay device having a logic element that outputs when only the output of the operation return verification element is input. 3. A protection relay for detecting an accident in a power system by comparing a scalar addition amount and a vector addition amount of each current amount taken in via a CT from a plurality of systems. A vector addition element for adding a vector, an effective value calculation element for deriving an effective value of the current amount of only the load line from an output of the vector addition element, and a current effective value of the derived effective value and a value earlier than the current value. A protection element for detecting the saturation of the CT by comparing the output of the protection element with the effective value, and locking the output of the relay by the output of the determination element. 4. A protection relay for detecting an accident in a power system by comparing a scalar addition amount and a vector addition amount of each current amount taken from a plurality of systems via a CT with a first determination element, wherein a load line is provided. A vector addition element for vector-adding each current amount of only the current value, an effective value calculation element for deriving an effective value of the current amount of only the load line from an output of the vector addition element, a current effective value of the derived effective value A second determination element for detecting the saturation of the CT by comparing the value with the effective value before the current, and detecting the saturation of the CT by determining whether the derived effective value is larger or smaller than a predetermined value. And a logical OR element for performing an OR operation on the output of the second determining element and the output of the third determining element, and locking the relay output by the output of the OR element. Special Protection relay device. 5. A protection relay for detecting a fault in a power system by comparing a scalar addition amount and a vector addition amount of each current amount taken from a plurality of systems via a CT using a first determination element, wherein a load line is provided. Vector addition element for vector addition of each current amount of only the first effective value calculation element for deriving the effective value of the current amount of only the load line from the output of this vector addition element, and this first effective value calculation element A second determination element for detecting the saturation of the CT from the derived effective value, and an effective value of the current amount of only the load line from an output of the vector addition element using an algorithm different from that of the first effective value calculation element. A second effective value calculation element to be derived, a third determination element for detecting the saturation of the CT from the effective value derived by the second effective value calculation element, and an output of the second determination element and the second determination element. Judgment of 3 is necessary A protection relay device comprising a logical sum element for performing a logical sum of an output of the element and an output of the logical sum element to lock a relay output. 6. A protection relay for detecting an accident in a power system by comparing a scalar addition amount and a vector addition amount of each current amount taken from a plurality of systems via a CT with a first determination element, wherein a load line is provided. A vector addition element for vector addition of only each current amount, an effective value calculation element for deriving an effective value of the current amount only for the load line from an output of the vector addition element, and a saturation of the CT from the derived effective value. A second determination element to be detected, and a determination function different from the second determination element is used to determine whether the effective value derived by the effective value calculation element is larger than a predetermined value, thereby detecting the saturation of the CT. A third determination element that determines the magnitude of the difference between the current output and the output before the current among the outputs of the vector addition amount of the vector addition element, and determines the magnitude of the difference between the second output and the second output based on the determination result. The fourth controlling the output of the third judgment element
And an OR element for inputting each output of the second and third judgment elements controlled by the fourth judgment element, and locking the relay output by the output of the OR element. Features a protective relay device.